If Stiness coefficent L/2a is greater than 1.5 ( in my case it is coming L/2a= 22.03

1. then which graph we have to refer , because only two graph are given for L/2a= 1.0 & 1.5 in Appendix. P.

2. Is Appendix P applicable for Nozzle not at bottom .

Well the Code does say "low tank nozzles". My personal interpretation of this is that this means "the bottom course".

If L/2a is greater than 1.5, use the curve for 1.5.
If L/2a is less than 1.0, use the curve for 1.0.
If L/2a is between 1.0 and 1.5, interpolate between the two curves.